There have been a variety of proposed dyes for use as polymerizable compounds to affect the colorization of optical plastics for lenses and ocular devices. Most of these relate to various diphenyl azo or triphenyl diazo compounds and generally claim to provide UV protection as well as blue light blocking capability because of their absorption of light in the 400-500 nm range. Because the human crystalline lens is pale yellow in color in young people and darker yellow to brownish yellow color in older people, these dyes serve the purpose of providing UV protection in addition to blue light filtering capability.
A need exists to provide, for example, discrete structures which absorb light below 500 nm or to a greater extent in the 400 nm to 500 nm range in order to more closely resemble the light filtering characteristics of the human crystalline lens of aged persons.